Root canal therapy requires that the infected root canal be cleaned to remove dead or diseased pulp and that the cavity thereby created in the root be filled with a material which fits tightly into the void space. Present techniques of root canal therapy essentially involve the initial cleaning of the canal using a series of small tapered files of increasing size to clear the canal. This procedure is then followed by the fitting and final insertion of the filler material into the canal. Frequently, the filler used for root canals is an elastomeric composition such as gutta percha which is supplied to the dentist in small tapered lengths of standard size which correspond generally to the size of the small tapered files that are used to clean the canal. These preformed fillers frequently however are not of exactly the right dimensions or configuration to provide the required exact fit in the canal and must therefore be trimmed by the operating dentist until the proper dimension is achieved to completely fill the excavated canal.
Present procedures for shaping and fitting root canal fillers involve essentially a trial and error operation in which the approximate length of the root canal is first determined by X-ray and by inserting into the infected canal the small tapered files used for cleaning, progressing to larger and larger files until the canal is completely free of necrotic debris. The standard filler is then marked at the same length as that portion of the file which was inserted into the canal. This procedures does not, however, always result in a filler having the appropriate lateral dimensions to fit the root canal and it is therefore frequently necessary to make further trimmings and adjustments until the exact fit is reached. All of this is difficult since the material being manipulated is flexible, and the procedure is time consuming for the dentist and therefore expensive for the patient.
A device for trimming different lengths of root canal filler is for example described in U.S. Pat. No. 4,255,142 to Aoyagi. U.S. Pat. No. 3,863,345 to Malmin also describes a system for root canal therapy which involves insertion of sealing material by means of an instrument into the excavated root canal.